Tubing joint and uses thereof

ABSTRACT

There is provided a tubing joint for use in breaking up scale and debris in fluids circulating within an oil, gas, water or other well to prevent clogging. The tubing joint has a tubular that defines a bore through which fluids flow, and a projection coupled to the tubular and extending into the bore. In some cases, the projection comprises a plurality of projections. The projection forms a partial obstruction within the bore of the tubing joint, against which scale and debris impact as they are carried by the fluid through the bore. Generally, the scale and debris break apart into smaller pieces upon impact, preventing the scale and debris from building up and causing a clog within the oil, gas water or other well.

CROSS-REFERENCE

This patent application claims priority from and the benefit of CanadianPatent Application No. CA 3,060,488, filed Oct. 29, 2019 andincorporates the same by reference.

FIELD

The present disclosure relates generally to well equipment forboreholes. More particularly, the present disclosure relates to a tubingjoint adapted to engage and break apart debris and uses thereof.

BACKGROUND

Wells, such as, for example, oil and/or gas wells in the oil and gasindustry can become clogged by scale and other debris. Scale can becaused by a deposition of, for example, various salts, oxides,silicates, and/or phosphates onto surfaces within a well, such as an oilwell, a gas well, a water well, etc. Some specific, non-limitingexamples of scale include metal salts and oxides, such as calciumcarbonate, calcium sulfate, barium sulfate, strontium sulfate, ironsulfide, iron oxides, etc.

Wells with considerable hard scale and debris are particularlysusceptible to clogging during clean out operations. When well boreclean out operations are conducted using reverse circulation, drillingfluids are reverse circulated down an annular space between a clean outstring and the well casing, with the fluid and any debris returning tothe surface through the “bore” of the clean out string. On occasion,debris and scale can bridge off and clog tubulars of the clean outstring. Clogging of tubulars is more common when the debris containslarge pieces.

There remains a need for equipment that prevents or reduces risk ofclogging during a clean out operation of operation of an oil and/or gasor other types of well.

SUMMARY

Herein described is a tubing joint that can be used to break up piecesof scale and debris carried by fluids circulating within tubing of awell, such as an oil well, gas well, or water well, thereby reducing therisk of the well clogging. The tubing joint comprises a tubular forcirculating a fluid, the tubular defining a bore through which the fluidflows, and a projection coupled to the tubular and extending into thebore. In some examples, the projection comprises a plurality ofprojections. As it extends into the bore of the tubing joint, theprojection forms a partial obstruction that engages and breaks apartscale and debris as it is carried by the fluid through the bore.

Generally, as a well is subject to reverse circulation of fluid, atleast a portion of the scale and/or debris in the wellbore flows intothe bore of the tubing joint and at least some of the scale and/ordebris breaks apart to at least some degree due to impacting theprojection(s), and the scale and/or debris are at least partiallyremoved from the wellbore by the reverse circulation of fluids up theclean-out string to surface. In an embodiment disclosed, the scaleand/or debris substantially breaks apart and is substantially removedfrom the wellbore.

In a first aspect, the present disclosure provides a tubing joint,including a downhole tubular, defining a bore therethrough, and aprojection coupled to the tubular and extending into the bore, theprojection forming a partial obstruction of the bore, adapted to engageand break apart debris in a fluid flowing through the bore.

In an embodiment disclosed the projection extends radially into thebore.

In an embodiment disclosed the projection comprises a plurality ofprojections.

In an embodiment disclosed each of the plurality of projections iscircumferentially displaced relative to each other.

In an embodiment disclosed each of the plurality of projections islongitudinally displaced relative to each other.

In an embodiment disclosed each of the plurality of projections iscircumferentially and longitudinally displaced relative to each other tospiral within the bore.

In an embodiment disclosed the projection extends into the bore betweenabout 10 percent and about 30 percent of the diameter of the bore.

In an embodiment disclosed the projection extends into the bore betweenabout 15 percent and about 25 percent of the diameter of the bore.

In an embodiment disclosed the projection extends into the bore about 20percent of the diameter of the bore.

In an embodiment disclosed the projection is substantially frustoconicalshaped.

In an embodiment disclosed the projection is substantially cone shaped.

In an embodiment disclosed the projection is substantially wedge tipped.

In an embodiment disclosed the projection is substantially nub shaped.

In an embodiment disclosed the projection is composed of tungstencarbide, carbon steel, stainless steel, hardened metal or combinationsthereof.

In an embodiment disclosed the projection is welded to the tubular.

In an embodiment disclosed the projection is integral with the tubular.

In an embodiment disclosed the tubular is a joint of tubing.

In an embodiment disclosed the tubular has a pin fitting at a first endand a bell fitting at a second end.

In a further aspect, the present disclosure provide use of the tubingjoint disclosed herein in a clean out string to remove debris from awellbore.

In an embodiment disclosed the tubing joint is used to break up debrisin a fluid in a well.

In an embodiment disclosed the debris comprises hard scale.

In a further aspect, the present disclosure provides a method forservicing a well having a defined wellbore containing debris, the methodincluding inserting a clean-out string into the wellbore, the clean-outstring including a tubing joint as disclosed herein, and reversecirculating a fluid through the well, and rotating the tubing joint toengage the debris with the projection within the bore, wherein at leasta portion of the debris is thereby broken apart into broken debris.

In an embodiment disclosed the method includes carrying the brokendebris out of the well with the fluid.

In an embodiment disclosed, inserting the clean-out string into thewellbore includes positioning the tubing joint within the wellboreproximate the debris.

In an embodiment disclosed, inserting the clean out string into thewellbore comprises positioning the tubing joint within the wellborealong a bottom portion of the wellbore.

In an embodiment disclosed the fluid is a drilling fluid or a wellservicing fluid. In an embodiment, the drilling fluid or the wellservicing fluid may be water.

In an embodiment disclosed the well is an oil well, a gas well, an oiland gas well, or a water well.

In an embodiment disclosed the debris includes hard scale or well-bottomdebris or both.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the present disclosure will now be described, by way ofexample only, with reference to the attached Figures.

FIG. 1 depicts a partial cross-sectional, side-elevation view of atubing joint (100) in accordance with an embodiment of the presentdisclosure, showing a face view (4) and back view (5) of a plurality ofprojections coupled to a tubular and extending into the bore thereof.

FIG. 2 depicts (A) a perspective view of a tubing joint in accordancewith an embodiment of the present disclosure, showing backside weldscoupling a plurality of projections to a tubular; and (B) across-sectional view of the tubing joint of (A), showing the pluralityof projections welded to the tubular and extending into the bore of thetubular.

FIG. 3 depicts a perspective view of a tubing joint in accordance withan embodiment of the present disclosure in use in a wellbore.

DETAILED DESCRIPTION

A tubing joint as described herein may be used to break up scale anddebris in a fluid circulating within a well, within a defined wellbore,including but not limited to cased wellbores, uncased wellbores, andcombinations thereof including but not limited to wellbores withbarefoot completions, the wellbore being a wellbore of, for example, ahydrocarbon recovery well (e.g. producing one or more of oil, gas andwater), a water well, an injection well, or a waste disposal well,thereby reducing the risk of the well clogging. Generally, clean outfluid is circulated down an annulus between the joints or length of acleanout string and the well bore wall, the tubular defining a borethrough which the returning fluid flows to the surface; and a projectioncoupled to the tubular and extending into the bore. The projection(s)form a partial obstruction of the bore to engage and break apart scaleand debris as it is carried through the tubing joint by the fluidflowing through the bore. Typically the scale and debris break apartupon impact with the projection(s). Rotation of the cleanout string (andthus the tubing joint) during the operation, greatly increases theeffectiveness of the operation due to the kinetic impact of debrischunks with the projection(s). In an example, the projection comprises aplurality of projections.

FIG. 1 shows a tubing joint 100 having a tubular 1, the tubular 1 is ajoint of tubing defining a bore 2, and having a bell and pin fitting 7,8 at either end. A coupling 7 couples the tubular 1 to another tubular.The tubing joint 100 has a projection 3 coupled to the tubular 1 andextending radially into the bore 2. The projection 3 comprises aplurality of projections, each of the plurality of projections beingcircumferentially and longitudinally displaced relative to each other tospiral within the bore 2. In other examples, each of the plurality ofprojections is longitudinally displaced relative to each other, andoriented in a spiral throughout a body of the tubular 1. In someinstallations, the projections may be oriented in a “spiral” shapethroughout the body of tubular 1.

FIG. 2 shows the tubing joint 100 with the projection 3 extendingradially into the bore 2 and comprising a plurality of projections. Theprojection 3 is coupled to the tubular 1 by a backside weld 9, and issubstantially cone-shaped. As best seen in an end-view of FIG. 2, theprojection 3 extends into the bore 2 of the tubular 1. The extensioninto the bore is preferably between about 10 percent and about 30percent of the diameter of the bore 2, more preferably between about 15percent and about 25 percent of the diameter of the bore 2, and morepreferably about 20 percent of the diameter of the bore 2. For example,if the bore 2 is 100 mm, then the extension into the bore 2 ispreferably between about 10 mm and about 30 mm, preferably between about15 mm and about 25 mm, and more preferably about 20 mm. Each of theplurality of projections 3 is circumferentially and longitudinallydisplaced relative to each other to spiral within the bore 2. In someapplications, the projections are oriented in a “spiral” shape. Theprojection into the bore 2 varies, depending on the service conditionsand the nature of the debris. In some examples, the projection(s) 3 aresubstantially frustoconical-shaped or substantially wedge-tipped. Insome examples, the projection(s) 3 are composed of tungsten carbide or ahardened metal or a combination thereof. The hardened metal may be, forexample, carbon steel or stainless steel. In some examples, theprojection(s) 3 are integral with the tubular 1. The projection(s) 3need not be of uniform lengths throughout the tool and may vary. In apreferred embodiment, the projection(s) 3 are relatively uninform tomaintain rotational balance of the tubing joint 100 to reduce vibrationin operation. In an embodiment disclosed, the tubing joint 100 isrotationally balanced, for example by design and/or addition of weightsand/or removal of material from the tubing joint 100.

Referring to FIG. 3, tubing joint 100 is attached to tubing string orclean-out string 25 and inserted into a wellbore 30 until proximate, at,or beyond debris 40. Debris 40 may be loose within the wellbore 30and/or at the bottom of the wellbore, freed by contact with the tubingjoint 100 and/or the string 25 and/or another clean-out tool (notshown), or freed by reverse circulation or circulation of the fluid 50.At least a portion of the debris 40 is broken up, and preferably thedebris 40 is broken up to provide broken debris 60. In an embodimentdisclosed, for example, broken debris 60 is sufficiently reduced in sizeto readily flow up the bore of the clean-out string 25. Reversecirculation of fluid 50 sweeps or otherwise conveys the broken debris 60and/or debris 40 into the tubing string or clean out string and to thesurface. While FIG. 3 illustrates the wellbore 30 as being asubstantially vertical portion, the invention may also be applied towells having slanted, horizontal, lateral, angled, dogleg, and/orradiused sections. The tool can be deployed in any orientation, providedthe longitudinal axis of the tool is aligned with the longitudinal axisof the well. While FIG. 3 illustrates the wellbore 30 as having a casing70, as described herein, the invention may also be applied to uncasedwellbores. In an embodiment disclosed, an inlet section 75, below thetubing joint 100, may be provided to accelerate or increase the velocityof the fluid 50 and therefore the debris 40 flowing inside the clean-outstring 25 towards the projections 3.

In an example, as generally depicted in FIG. 3, in use the tubing joint100 may form part of a tubular string, such as a completion or workoverstring, referred here generally as a clean-out string 25 that is beingused to service a well in a formation 35, such as an oil well, gas well,or water well, that has an amount of scale or debris and may be at riskto become clogged; for example, as part of conventional service rigclean out operations. Particularly, the tubing joint 100 may form partof a completion or workover string or clean-out string 25 at a pointclose to the bottom of the well, and may rotate with the string 25. Thetubing joint 100, for example, may be used in a well clean-outoperation. Typically during such a clean-out operation, fluid(s), suchas a drilling fluid or well-servicing fluid, or water is reversecirculated down an annulus formed between a wellbore of the well and thecompletion string, with the fluid returning up the completion stringbore (indicated by arrows in FIG. 3). When the tubing joint 100 formspart of the clean-out string, at least some of the scale or debris beingcarried by the drilling fluid up the clean-out string 25 will impact orotherwise contact the projection 3 extending into the bore 2. Asillustrated in FIG. 3, a plurality of projections 3 may be coupled tothe tubular 1. By impacting the projection 3, the scale or debris may bebroken into smaller pieces, thus inhibiting their tendency to bridge offand clog tubulars of the completion string.

In another example, in use the tubing joint 100 is added to aconventional well clean-out string, and is used to assist with breakingup large pieces of scale and other well-bottom debris that, during aclean out operation, are reverse circulated out of the well. As usedherein, a clean-out string is a string of tubulars, for example tubing(e.g., coiled tubing or jointed tubing), assembled to clean out a well(e.g., an oil well, gas well, water well) that has its performancerestricted or otherwise reduced by well-bottom debris. The clean-outstring is generally set up by a service rig attending the wellsite. Forexample, if in use, a production tubing string is first removed from theaffected well and set aside in a suitable manner. Tubing joint 100 isadded to the clean-out string as close as possible to the bottom of thestring, and is torqued up to a make-up torque suitable for the threadsof the clean-out string. In an example, the tubing joint 100 is used inconjunction with some form of clean-out bit that is suitable for useduring, for example, at least reverse circulation. The clean-out stringis then inserted into, for example, the casing 70 of the affected welland lowered to the point of debris obstruction. Standard industry wellservicing practices may be followed during the insertion of theclean-out string. Once the clean-out string is located at the point ofdebris obstruction, the clean-out string is rotated, and the well isreverse circulated with well-servicing fluid being pumped down to thewell-bottom through the annulus between the string and the casing. Thewell-servicing fluid returns to the surface through the center bore ofthe clean-out string, including through the bore 2 of the tubing joint100. As would be understood by a person skilled in the art, thewell-servicing fluid pump rates need to be sufficient to create a fluidvelocity that will carry debris up through the center bore of theclean-out string. At the same time that the well is being reversecirculated, the clean-out string is rotated to create a grinding actionif a clean-out bit is used, or to create additional well-bottomturbulence when a clean-out bit is not used, or to increase the dynamicimpact of the scale or debris with the projections, where commonindustry practice would determine the rotation rate. Projection 3 oftubing joint 100 are impacted by debris as the debris is carried upthrough the clean-out string. The rotating action of the clean-outstring increases the debris-impacting performance of the tubing joint100. As the debris impacts the projection 3, the debris is broken apartinto smaller pieces, greatly reducing the potential that the debris willbridge off and clog the clean-out string. Upon completion of the cleanout, the clean-out string is pulled out of the well bore, and the tubingjoint 100 is inspected and set aside for use in another well servicejob. The service string is then reinserted into the well bore and wellput back into service.

The tubing joint 100 may be used in a completion string. The tubingjoint 100 may be used in an oil and/or gas well. The tubing joint 100may be used to break up debris in a fluid in an oil and/or gas well,where the fluid may be a drilling fluid or a clean out fluid and thedebris may comprise hard scale.

Generally, the downhole tool may be used with tubulars, including butnot limited to pipe, drill pipe, tubing, coiled tubing, jointed tubing.Generally, the downhole tool may be rotated if, and as necessary fromthe surface, for example by a top drive or rotary table. The downholetool may be used with tubulars rotated proximate the downhole tool, forexample by a mud motor or downhole-motor, but such arrangement wouldrequire an ability to reverse circulate and accommodate the debris.Accordingly, rotation of the tubular (and tool) from the surface ispreferred. The supply of well servicing fluid, and circulation orreverse circulation, as the case may be, as well as the removal ofdebris from the well servicing fluid, is provided from/at surface. Thedownhole tool may form part of the string or may be at or near thebottom end of the string. One or more of the downhole tools may beprovided in the string.

Generally, in an embodiment disclosed, the projections may consist ofcutting tools, cutting inserts and/or cutting elements, for example madeof tungsten carbide (WC), blended tungsten carbide-cobalt or cementedcarbide products, for example but not limited to shaped inserts that maybe attached to the inside of the tubular by welding, bonding or brazing.

Apart from hard scale, well-bottom debris may be loose debris that mayoriginate from one or more sources within or associated with thewellbore. It may be hard debris that originates from within thecompleted formation or from formation fluids. Occasionally, hard scaleor well-bottom debris could result from mechanical debris from wellborecomponents. It could be scale, consolidated or unconsolidated sand, ironsulfides, wax or a combination of one or more of the above. When thematerial is hard, the disclosed tool and methods break it up.

Embodiment 1. A tubing joint, comprising a downhole tubular, defining abore therethrough; and a projection coupled to the tubular and extendinginto the bore, the projection forming a partial obstruction of the bore,adapted to engage and break apart debris in a fluid flowing through thebore.

Embodiment 2. The joint of embodiment 1, wherein the projection extendsradially into the bore.

Embodiment 3. The joint of embodiment 1 or 2, wherein the projectioncomprises a plurality of projections.

Embodiment 4. The joint of embodiment 3, wherein each of the pluralityof projections is circumferentially displaced relative to each other.

Embodiment 5. The joint of embodiment 3 or 4, wherein each of theplurality of projections is longitudinally displaced relative to eachother.

Embodiment 6. The joint of any one of embodiments 3 to 5, wherein eachof the plurality of projections is circumferentially and longitudinallydisplaced relative to each other to spiral within the bore.

Embodiment 7. The joint of any one of embodiments 1 to 6, wherein theprojection extends into the bore between about 10 percent and about 30percent of the diameter of the bore.

Embodiment 8. The joint of embodiment 7, wherein the projection extendsinto the bore between about 15 percent and about 25 percent of thediameter of the bore.

Embodiment 9. The joint of embodiment 8, wherein the projection extendsinto the bore about 20 percent of the diameter of the bore.

Embodiment 10. The joint of any one of embodiments 1 to 9, wherein theprojection is substantially frustoconical shaped.

Embodiment 11. The joint of any one of embodiments 1 to 9, wherein theprojection is substantially cone shaped.

Embodiment 12. The joint of any one of embodiments 1 to 9, wherein theprojection is substantially wedge tipped.

Embodiment 13. The joint of any one of embodiments 1 to 9, wherein theprojection is substantially nub shaped.

Embodiment 14. The joint of any one of embodiments 1 to 13, wherein theprojection is composed of tungsten carbide, carbon steel, stainlesssteel, hardened metal or combinations thereof.

Embodiment 15. The joint of any one of embodiments 1 to 14, wherein theprojection is welded to the tubular.

Embodiment 16. The joint of any one of embodiments 1 to 14, wherein theprojection is integral with the tubular.

Embodiment 17. The joint of any one of embodiments 1 to 16, wherein thetubular is a joint of tubing.

Embodiment 18. The joint of any one of embodiments 1 to 17, wherein thetubular has a pin fitting at a first end and a bell fitting at a secondend.

Embodiment 19. Use of the tubing joint of any one of embodiments 1 to 18in a clean out string to remove debris from a wellbore.

Embodiment 20. Use of the tubing joint of any one of embodiments 1 to 18to break up debris in a fluid in a well.

Embodiment 21. The use of embodiment 19 or 20, wherein the debriscomprises hard scale.

Embodiment 22. A method for servicing a well having a defined wellborecontaining debris, comprising: inserting a clean-out string into thewellbore, the clean-out string including a tubing joint of any one ofembodiments 1 to 18; and reverse circulating a fluid through the well;and rotating the tubing joint to engage the debris with the projectionwithin the bore, wherein at least a portion of the debris is therebybroken apart into broken debris.

Embodiment 23. The method of embodiment 22, further comprising carryingthe broken debris out of the well with the fluid.

Embodiment 24. The method of embodiments 22 or 23, wherein inserting theclean-out string into the wellbore comprises positioning the tubingjoint within the wellbore proximate the debris.

Embodiment 25. The method of any one of embodiments 22 to 24, whereininserting the clean out string into the wellbore comprises positioningthe tubing joint within the wellbore along a bottom portion of thewellbore.

Embodiment 26. The method of any one of embodiments 22 to 25, whereinthe fluid is a drilling fluid or a well servicing fluid.

Embodiment 27. The method of any one of embodiments 22 to 26, whereinthe well is an oil well, a gas well, an oil and gas well, or a waterwell.

Embodiment 28. The method of any one of embodiments 22 to 27, whereinthe debris comprises hard scale or well-bottom debris or both.

The embodiments described herein are intended to be examples only.

Alterations, modifications and variations can be effected to theparticular embodiments by those of skill in the art. The scope of theclaims should not be limited by the particular embodiments set forthherein, but should be construed in a manner consistent with thespecification as a whole.

All publications, patents and patent applications mentioned in thisspecification are indicative of the level of skill those skilled in theart to which this invention pertains and are herein incorporated byreference to the same extent as if each individual publication patent,or patent application was specifically and individually indicated to beincorporated by reference.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodification as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A tubing joint, comprising a downhole tubular,defining a bore therethrough; and a projection coupled to the tubularand extending into the bore, the projection forming a partialobstruction of the bore, adapted to engage and break apart debris in afluid flowing through the bore.
 2. The joint of claim 1, wherein theprojection extends radially into the bore.
 3. The joint of claim 2,wherein the projection comprises a plurality of projections.
 4. Thejoint of claim 3, wherein each of the plurality of projections iscircumferentially displaced relative to each other.
 5. The joint ofclaim 4, wherein each of the plurality of projections is longitudinallydisplaced relative to each other.
 6. The joint of claim 5, wherein eachof the plurality of projections is circumferentially and longitudinallydisplaced relative to each other to spiral within the bore.
 7. The jointof claim 6, wherein the projection extends into the bore between about10 percent and about 30 percent of the diameter of the bore.
 8. Thejoint of claim 7, wherein the projection extends into the bore betweenabout 15 percent and about 25 percent of the diameter of the bore. 9.The joint of claim 8, wherein the projection extends into the bore about20 percent of the diameter of the bore.
 10. The joint of claim 9,wherein the projection is substantially frustoconical-shaped.
 11. Thejoint of claim 9, wherein the projection is substantially cone-shaped.12. The joint of claim 9, wherein the projection is substantiallywedge-tipped.
 13. The joint of claim 9, wherein the projection issubstantially nub-shaped.
 14. The joint of claim 9, wherein theprojection is composed of tungsten carbide, carbon steel, stainlesssteel, hardened metal or combinations thereof.
 15. The joint of claim14, wherein the projection is welded to the tubular.
 16. The joint ofclaim 14, wherein the projection is integral with the tubular.
 17. Thejoint of claim 9, wherein the tubular is a joint of tubing.
 18. Thejoint of claim 17, wherein the tubular has a pin fitting at a first endand a bell fitting at a second end.
 19. In a tubing joint, comprising: adownhole tubular, defining a bore therethrough; and a projection coupledto the tubular and extending into the bore, the projection forming apartial obstruction of the bore, adapted to engage and break apartdebris in a fluid flowing through the bore, the use of the tubing jointin a clean-out string to remove debris from a wellbore.
 20. The use ofclaim 19, wherein the debris comprises hard scale.
 21. In a tubingjoint, comprising: a downhole tubular, defining a bore therethrough; anda projection coupled to the tubular and extending into the bore, theprojection forming a partial obstruction of the bore, adapted to engageand break apart debris in a fluid flowing through the bore, the use ofthe tubing joint to break up debris in a fluid in a well.
 22. The use ofclaim 21, wherein the debris comprises hard scale.
 23. A method forservicing a well having a defined wellbore containing debris,comprising: inserting a clean-out string into the wellbore, theclean-out string including a tubing joint comprising: a downholetubular, defining a bore therethrough; and a projection coupled to thetubular and extending into the bore, the projection forming a partialobstruction of the bore, adapted to engage and break apart debris in afluid flowing through the bore; and reverse circulating a fluid throughthe well; and rotating the tubing joint to engage the debris with theprojection within the bore, wherein at least a portion of the debris isthereby broken apart into broken debris.
 24. The method of claim 23,further comprising carrying the broken debris out of the well with thefluid.
 25. The method of claim 24, wherein inserting the clean-outstring into the wellbore comprises positioning the tubing joint withinthe wellbore proximate the debris.
 26. The method of claim 25, whereininserting the clean-out string into the wellbore comprises positioningthe tubing joint within the wellbore along a bottom portion of thewellbore.
 27. The method of claim 26, wherein the fluid is a drillingfluid or a well-servicing fluid.
 28. The method of claim 23, wherein thewell is an oil well, a gas well, an oil and gas well, or a water well.29. The method of claim 23, wherein the debris comprises hard scale orwell-bottom debris or both.